Apparatus for attaching filaments to electrodes in machines for coating with metal vapors



y 5, 1953 2. M. SHAPIRO 2,637,298

APPARATUS FOR ATTACHING FILAMENTS TO ELECTRODES IN MACHINES FOR COATING WITH METAL VAPQRS Filed NOV. 20 1851 2 SHEETSSHEET FIG. I.

.Illllllllll FIG. 2.

FIG. 3.

Z5 .27 INVENTOR ZALMAA/M $J1AP1R0 ATTORNEY y 5, 1953 2 M SHAPIRO 2,637,298

APPARATUS FOR ATTA CHfNG FILAMENTS TO ELECTRODES IN MACHINES FOR COATING WITH METAL VAPORS 2 SHEETS-SHEET 2 FiledvNov. 2O 1951 FIG. 7.

FIG. 6.

FIG. 4.

r\ n o\ v INVENTOR ZALMAN M $HAP1R0 ATTO RNEY Patented May 5, 1953 UNITED STATES PATENT OFFICE lzgssms'k APPARATUS For: ATTACHING FILAMENTS TOELECTRODESJIN MACHINES FOR COAT- ING WITH METAL VAPORS illnian Sharing-b", Pittsbui'gh, Pa., assignor, by niesne assignments to the United States of Amer'iea as i'epl'es'ented y the United States Atomic Energy Commission Abbli'atibn ltbvemti- 20,1951, Serial No. 251309 1 7 Claims. This invehtion reiate's 'to of pieeipitatih meals lv, r i d b si mn 'Q 9misauna thei'eoi ahd niorepaitieulariy to a new and improved apparatus for mounting the filament or starting 'wire employed in the well known hot-wire"? piocess. Inimy cop-ending application foi' United States Letters lf'atent, Serial Nun1ber 25 7,308, filed November 20, 1951, the i'edniteineiits for 'siieh ah apparatus are set forth and a novel and useful means foimeeting such i'e'quii enlerits is disclosed. However, despite the fact that the apparatus shoivn in that application juifilis a length; need it has been io md that the 'electiode tif) therein shown isi elatively expensive in that it normally is intended for use 611132 on one occasion, and is fnad'e of a x elatively ek'pens'ive niaterial and the cost of machining the same is'felativeiy high. h

The present ihventioh as ah Object the pr-evasion of a new and. ilfhpi ovecl means for atta'ohing a hot-wine filament to an electrode and oom p risihg a Yensabl'e adaptornnit. U A second object is the pi'ovi'sion of an electrode tip assembly for attachihg a hot wi e filanient to an electrode through the intermediary of easily as's'embiefi and disassembled o ni rent barryin'g elements which are relatively inexpene n i e b it U H o .i A thii-d object is the pr'ovisio of a new and mproves abp'a 'ath's yer attaching a hot-wire ill. Merit to as lectrode by nie'ansof separ his a h a ne i imi beet eqe ei v i ans to niovide ein i'ent be itting eapaoitiin'ac? oi'daho with the ohahging needs at varioiis stages of th metal clepositioh. a I w H O e1 bbjts and advamages w ig hec'o ne noije abfiarent as the cleseiifition htoeeedfs when ebss aeiee in con jpnetio'n with the accompanyiag li'awinij's in Whi'chi v u U U Figure 1 is a View, fiaitly i151 seetioii, shovving a vessel in whioh thermal decomposition of "a ifietal cofnbound for hothtir deposition of the metal may e cari ie tl ont using the iiiibr'o've'd abijafatusfoi my inventioni A Figinf 2 is top plan vi'ew oi one ioi'xn fii adaptor embodying oertain features of the iiiwhen: .v i Figure 3 is a 'sctiohalview of the ad'antof taken oh line 3 3 of fie-pie 2 v H W I Fi'gn're 4 is a fifoiit elevation view showing ahothei shit abie farm a: adaptor with attached fineiem'ents; V I I Figui 5 is a toi plan View of the adaptor shown iii Figure 4; V l

Figure 6 is a side elevation of the adaptor and finsshowii in Figure 4;

2 s Figure 7 is a side elevation of the adaptor ancifi s of Figurehut showing an alternate arrangement for anchoring the hot-wire filamenma'nd w Figure 8 is an elevation View of a spaoe'r element employed withth'e fins and adaptor, H 7 Referring now to Figure l, a suitable vessel or reaction ohanihe'r lil having an associated heating means I I, is provided for containing the, vapor of the metal compound. A "cohdlii't i2 leaoiingto an evacuatin'gine'ans amen i3 suitablysealed upon the flanged edge oi the vessel are preferably employed to the en that a desired metal compound may be placed in the vessel, and contaminating air a thereafter be drawn out o f the vesselpri'or to the forma tion of the nie'tal vapor resulting from ester: n'ally applied heat allin the manner known in he, art. As will Ioe apparent to those skilled in this art, certain standard precautions will he observed in carryingoutth pfocess especially in View of the highly horrosive natnrepf liberateclgas evolved from the metal compound. The material used in construction of vessel 10 and other, exposed apparatus will accordingly heseltactedwvith this feature in mind. Fo example, in the cyclic iodide process of preparing ductile zirconium, the z ireonium to be deposited together with a small amount of iodine orgie- 9011mm iodide, may beloaded into vessel ip into cracking bottle which can he brokenaftei het il n l ed in the v ss A t sui a er s': nation "of the vessel the heating means It may be operated to pause a zirconium iodidevapor to permeate the vessel. Thereaftet the hot-wir fila nt l ter b r 'ib ii a s t e u t ahleten pei ature and 'th'e volatile zirconium tet 'aiodide will ciecompose on that wire leaving a deposit of elemental zil eonipni an i liberating elfeh ehtaliocline This iodine in tnrn 'clif fuses hack to the erudezh oonium material and ior ns more of the metallic iodide vapor which in turn diffuses to the Wire and is decomposed. In this way the seed filan ehtor wire has hnilt upon it a heavy gieposit oizirconinin iji'ovidd it oan be supported upon theelectrodes and oa'n constantly :teceive enough current to remain above the giecomposition temperature of the metal co npoungl vapor As set forth in detail in my oope dihg ease, above refefied to, if ex oessive heat flow by condiietion from the ends oithe hot-wire is permitted, the wire mav fali below the decomposition temperature at its ends whereupon the gas liberated from the decomposjable vapor, in the illustrative example, iodine, will then attack the deposit at this oooler paint.

In a short time the wire at this area will start to fuse since as more current is supplied to maintain the decomposition temperature at the other parts of the wire and its deposit this particular area of the wire will have insuiiicient current carrying capacity. To avoid this problem the present invention provides a suitable ratio of dimensions of current carrying structure as will become more apparent hereinafter.

There preferably is mounted within the lid of the vessel I two massive electrodes I4 and I suitably insulated from the vessel and having heavy leads I 0 and I! respectively connected thereto. These leads which may be called upon to carry currents in the order of 2000 amperes. or greater are suitably connected to a regulated source of electrical current permitting an appropriate increase in the fiow of current m the size of the deposited metal bar increases, thereby to permit the maintenance of such deposited metal at an appropriate temperature.

A starting wire or filament 20, also known as a hot-wire, is suspended within the space of the vessel and in accordance with my invention is connected at its ends to the electrodes by means of electrode tip structure comprising reusable adaptors 2i and 22 having attached expendable connector means now to be described. For simplicity of description there is shown in Figure 1 two alternate forms of such adaptors and connector means although, as will be obvious, either of these types may be used in pairs rather than using one of each type as shown.

As shown in Figures 2 and 3 and at the left hand electrode of Figure 1, one form of adaptor may comprise a cup shaped member 2! having a hollow upper portion 22 adapted to slip upon the exposed lower end of the electrode and to be reare shorter than wires 28, are likewise mounted and anchored at their upper ends in space 22. As will thus be seen, when this electrode tip assembly is first installed in vessel [0 electrical current can flow only through the electrode I4, adaptor 2I, looped wire 2! and filament to the other assembly on the other electrode I5. The spaced longer wires 28 and the spaced shorter wires 29 do not at this time participate in this current carrying circuit. However, as the deposited metal upon filament 20 increases in volume with the concomitant increase in diameter of that filament, the metal deposit bridges over from looped wire 21 to the adjacent projecting ends of the longer wires 28, and upon continuing the process a similar bridging later takes place between the deposit upon such wires 28 and the ends of the adjacent shorter wires 29. In this way a progressive growth in diameter of the deposited bar, with its'need for increased current carrying capacity and proper heat conductance, is accommodated by the progressive bridging afforded by the design of electrode tip. With this arrangement a bar of deposited metal having a diameter as large as 1 /8" may be grown with the assurance that the process will be carried out without interruption and that the heavy weight of the bar will be adequately supported without damage to the electrode.

The spacing of the Supporting wires as noted in Fi ure 2 is such as to insure a progressive bridging of the wires by the deposited metal and thus to build not only the current carrying ca-.

. pacity, but also the mechanical support as needed tained thereon by suitable set screws extending spaced apertures surrounding a centrally disposed aperture 24 extending through the adaptor body 2!. The spaced apertures preferably may be in two concentric rings as indicated by illustrative apertures and 20. Means for attaching the end of wire 20 to the adaptor will normally be located in the aperture 2 andmay take one of various forms. For example, the aperture 24 should be of the approximate outer diameter of Wire 20, which usually is about 0.080 to 0.095 inch. One means for attaching this wire may include a looped molybdenum connector wire 21 shown in Figure 3 and having its ends anchored within space 22 of the adaptor, the end of the wire 20 being attached in a suitable manner to the looped end of wire 21 at a point furthermost from adaptor 21 as seen in Figure l. A further variation may include the use of a small molybdenum tube, not shown, inserted in aperture 24 and through which the wire 20 may be inserted for anchoring within the space 22 of the adaptor.

For the purpose of providing increased current carrying capacity as needed and for supporting the heavy weight of the deposited bar as it grows to a size generally indicated by the dotted line in Figure l a series of molybdenum wires 23, preferably of unequal length, and each of which is shorter than the efiective length of connector wire 21, are mounted in apertures 25 and anchored at their upper ends in space 22. Similarly in apertures 25 a plurality of such wires 29, which and yet to limit the heat conducting capacityto a safe value simultaneously with growth of bar diameter. The diameter of the supporting .wires is not critical within reasonable limits. It has been found that wires of 0.080 inch diameter ,are satisfactory but if wires of more than twice this diameter are used their heat conductivity is much higher and zirconium may not grow on them.

Upon completion of the thus described deposition process the heater II may be disconnected, the sup-ply of current to the electrodes may be discontinued and the lid I3 of the vessel may be removed. By loosening the set screws in holes 23 the entire adaptor, connector and deposited metal assembly may be removed as a unit. In contrast with the invention in my above-mentioned application, however, it is possible to reuse the adaptor simply by sawing ofi the deposited bar, 'as by making a cut through the connector wire 21 and wires 28 and 29 below. the adaptor body 2 I, thus making the relatively expensive adaptor available for repeated usage. Merely by insertinga new set of such wires in the adaptor and by discarding the severed upper ends of the old wires, 9. new electrode tip assembly can be quickly provided.

Referring now to Figures 4 and 5 and to the right hand portion of Figure 1, there is shown an alternative arrangement comprising an adaptor 22 having a top portion 40 and a circumfer ential side groove 4| into which suitable fastening means, such as set screws 42, may be inserted in order to mount the structure detachably upon the electrode I5. The adaptor is provided with a plurality of parallel spaced rectangular apertures into which a plurality of thin fin members,

are adapted to be positioned and to extend therefrom into the interior of vessel I0. As shown in Figure 4. the centrally disposed fin member 43 preferably is longer than the immediately adjacent members 44 and 45 and at its lower end is provided with a suitable means for anchoring thereto one end of the starting wire 20. Other pairs of fin members such as 46, 41 and 48, 49 may be provided depending upon the mechanical support and the current carrying capacity required for the bar of metal to be deposited. In general, it is preferred to utilize tapered fin members, as best shown in Figure 6, although the taper provided for the fin anchoring the starting filament must permit a sufficient cross section to insure adequate support until the deposited metal begins to bridge the adjacent fins. Each fin is provided with shoulders such as shown at 50 resting upon a ledge 5| adjacent the upper portion 40 of the adaptor for the purpose of spacing the same properly. Intermediate each fin is a separate short spacer 52, such as shown in Figure 8, for maintaining this desired spacing. As in the earlier described modification of the invention, the fins preferably are made of a refractory metal such as molybdenum or of the same metal as the starting wire 20. Likewise, for the purpose of limiting the conduction of heat, the fins not only are tapered but also are of comparatively thin sheet metal, for example having a thickness of the order of 0.030 inch when a starting wire of 0.080 inch is employed. Various ways of attaching the starting wire to the central fin may be employed other than the riveted fastening shown in Figure 6. For example, a looped molybdenum wire 69, as best shown in Figure 7, may be positioned in a central fin having separated parts BI and 62 and the ends 53 and E4 of such looped wire may be anchored at the top 49 of the adaptor between adjacent spacers. The end of the filament or starting wire in this case may then be secured in any suitable way to the extending loop of the wire 60. By use of fins thus described, when the deposition of the desired bar of metal has taken place the bar may be severed from the adaptor 22 by cutting through the fins, the severed upper ends may be discarded and both the spacers 52 and the adaptor 22 may be reused.

As will be apparent, various changes in the construction and materials used in the adaptors, the fins and rods and the various spacing and fastening means may be made without departing from the scope of the invention. Moreover, the apparatus is in no way limited to the production of zirconium bars, but on the contrary may be used in the production of any metal using the hot-wire techniques. Accordingly, it is not desired to limit the invention to the exact details as shown except insofar as defined in the following claims.

What is claimed is:

1. In combination, a vessel adapted to contain a decomposable vapor of a metal compound, electrodes mounted within said vessel, a filament adapted to be maintained at a temperature above the decomposing temperature of said vapor by a current supplied to said electrodes, and means for attaching the ends of said filament to said electrodes, said means comprising a detachable adaptor attached to the electrode and a plurality of spaced members fixed at one end to said adaptor, one of said members having an end of said filament attached to the non-fixed end thereof and with the non-fixed ends of the remaining members suspended in space and terminating adjacent the point of attachment of said filament, whereby deposited metal may progressively bridge the spaces between the non-fixed ends of the members.

2. For use in the support of an enlarged deposit of metal by an electrode, an electrode tip assembly having an adaptor portion arranged to contact said electrode, means for releasably mounting said assembly upon said electrode, a plurality of spaced current carrying elements mounted at one end upon said adaptor portion, and means for attaching a hot-wire filament to the projecting end of one of said elements, the other end of the remaining elements being suspended in space and terminating adjacent the point of attachment of said filament, whereby deposited metal may progressively bridge the spaces between the ends of said elements as the size of the deposit is enlarged.

3. Apparatus as described in claim 2, wherein said elements comprise a series of wires.

4. Apparatus as described in claim 3, wherein at least one of said wires is longer than the remaining wires.

5. Apparatus as described in claim 2, wherein said elements comprise a series of comparatively thin tapered fins having the widest portion thereof attached to the adaptor.

6. Apparatus as described in claim 5, wherein at least one of said fins is longer than the remaining fins.

'7. An electrode tip assembly comprising an apertured adaptor member arranged for detachable mounting upon an electrode, a plurality of heat and electric current conducting metal elements extending through said apertures and spaced from each other, a centrally disposed element longer than the remaining said elements and adapted to connect with one end of a hotwire filament, the spacing of said elements permitting the bridging of the same by deposited metal on one side of said adaptor, and means detachably anchoring said elements at the opposite side of said adaptor whereby upon severing the deposited metal and bridged elements the remainder of said elements may be retracted through said adaptor thereby to permit the reuse of said adaptor.

ZALMAN M. SHAPIRO.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 745,122 Tone Nov. 24, 1903 1,218,042 Baily et al Mar. 6, 1917 1,222,593 Barnett et a1 Apr. 17, 1917 1,681,736 Kull Aug. 21, 1928 1,819,554 Hanson Aug. 18, 1931 2,551,341 Scheer et al May 1, 1951 

